[BUG] check for global.maxconn before doing accept()

If the accept() is done before checking for global.maxconn, we can
accept too many connections and encounter a lack of file descriptors
when trying to connect to the server. This is the cause of the
"cannot get a server socket" message  encountered in debug mode
during injections with low timeouts.
diff --git a/src/proto_uxst.c b/src/proto_uxst.c
index 0eaea3c..599252a 100644
--- a/src/proto_uxst.c
+++ b/src/proto_uxst.c
@@ -368,7 +368,7 @@
 	else
 		max_accept = -1;
 
-	while (max_accept--) {
+	while (actconn < global.maxconn && max_accept--) {
 		struct sockaddr_storage addr;
 		socklen_t laddr = sizeof(addr);